Field of the Invention
The present invention relates to a resist pattern forming method and a developer for lithography.
Description of Related Art
In lithography techniques, for example, a method is performed in which a resist film composed of a resist material is formed on a substrate, the resist film is subjected to selective exposure using light or radiation such as electron beams through a mask in which a predetermined pattern is formed, and a development treatment is performed such that a resist pattern having a predetermined shape is formed on the resist film.
A resist material in which a portion having undergone exposure turns into a portion having a property of being dissolved in a developer is referred to as a positive resist, and a resist material in which a portion having undergone exposure turns into a portion having a property of not being dissolved in a developer is referred to as a negative resist.
In recent years, in manufacturing of semiconductor devices or liquid crystal display devices, with the progress of lithography techniques, patterns have rapidly become finer.
For making a fine pattern, generally, a method of shortening the wavelength (increasing the energy) of an exposure light source is performed. Specifically, although ultraviolet rays represented by g-line and i-line were used in the related art, currently, mass production of semiconductor devices by using a KrF excimer laser or an ArF excimer laser has begun. Furthermore, due to these excimer lasers, short-wavelength (high-energy) electron beams, extreme ultraviolet (EUV), X-rays, and the like are also being investigated.
The development treatment in the resist pattern forming method described above is performed by alkaline development using an alkaline solution or organic solvent development using an organic solvent.
In the alkaline development, generally, an aqueous solution of tetramethylammonium hydroxide (hereinafter, described as “TMAH” in some cases) is used. In recent years, the use of an aqueous solution of tetrabutylammonium hydroxide (hereinafter, described as “TBAH” in some cases) has also been suggested.
Japanese Unexamined Patent Application, First Publication No. 2011-145561 discloses a developer for lithography, investigated in the past by the inventors of the present invention, containing an aqueous solution of TMAH and an aqueous solution of TBAH.